This invention has to do with a gripping cable hanger system for use in the solar, mining, and electrical industries. In solar, mining, and electrical industries there is a need for electrical cables to extend from a power or signal source to a location of application. Such cables are usually indirectly connected and supported by an independent, structurally supported messenger wire that is strung along the planned cable route. Solar plants comprise large arrays of solar panels spread out over a large area. Solar panels collect the sun's rays causing a direct current to flow to direct current wires that are attached to the solar panels and then the current flows to combiner boxes before extending further to power inverters. Along the same messenger wire alternating current power cables are used to power the motors that control the trackers, devices that rotate the solar panels to follow the sun in order to obtain maximum power during daylight hours.
Prior to 2014, AC and DC cables could be bundled immediately adjacent to, and touching, one another in a wire management system for the solar panels. In the new National Electric Code of 2014, the AC and DC cables must not be immediately adjacent to one another, but must have a degree of separation from one another. Power carrying cables have a tendency to induce errors or interfere with the signal wires that are located in close proximity to them.
This new requirement also applies to other applications outside the solar power industry, such as the mining and electrical industries.
Because of the increased use of trackers in solar power plants, there is increased use of category five cables and other data wiring. This type of control wiring is used to give power plant operators feedback from the solar power plant array on what angles the panels are stationed, and what the proper angle should be to maximize power output from the sun. This data and information is constantly monitored to obtain maximum power output from the thousands of solar panels in the solar power plant. The type of wiring used in collecting data is sensitive to cables used for AC and DC power and because of that sensitivity, data wiring cannot be bundled with power cables and must be supported by a separate carrier that is at least 1 inch away from all power cables.
In solar power plants, mining and other electrical applications, there are various sized wires and bundles of wires with an almost unlimited variety of wire bundle sizes. Bundle size is becoming very important in the manufacture of hangers to accommodate these various sizes, especially in multiple carrier hangers.
In the past, cable hangers had small open loops or modified open loops for partial attachment to a messenger while loading the cables onto the hangers and the open loops allowed the partially hung hangers to easily fall off the messenger wire if the hangers were bumped or hit the wrong way during the cable loading process. In a solar plant there is a recent move to tracker systems which utilize more wiring than previously fixed, in place, systems and there is also the new NEC code which went into effect Jan. 1, 2014, which states that all AC and DC wiring must now be separated in any hanging or support system. Because of these changes, the wire management systems are much more complex, especially given the vast number of wires involved in a utility scale solar power plant. With these changes, the hangers are initially installed on the messenger wire and the bundles of cables are loaded separately in the carrier or carriers of the hanger. This process continues until all individual cables and bundles of cables are supported in the hangers. In the process of loading cables, the hangers are constantly bumped and jostled as they are loaded with bundles of cables. Prior styles of hangers that might have been used could easily fall off the messenger wire when bumped if only hanging by one open loop during cable installation.
The new NEC code requires any cable support system to have supports that are spaced at no greater than 30 inch intervals. This applies to cable trays, hangers or all other types of cable support systems. The prior hangers with their open style loops can fall off easily during installation and also could easily slide out of the desired 30 inch spacing when loading the cables. This is a more serious problem when you consider that there are tens of thousands of hangers being installed in the desert heat which can reach 120° F. Any wasted labor is a high additional cost in this environment.
A major factor affecting labor costs during installation of cables is how easily the electrician can load the cables and bundles of cables in the hangers in the stifling heat of the desert where solar power plants are usually located. Styles of cable hangers presently on the market can easily swing from side to side as they are initially engaged and suspended on the messenger wire requiring an electrician to take one hand and properly align the hanger in a 90° perpendicular orientation to the messenger wire in order to load the cables or bundles of cables in the hanger with the other hand. This two handed process of aligning the hanger increases the time necessary to load cables over the thousands of feet of messenger wire with the hangers on 12 inch centers.